text: /*
   * Copyright © 2016 Intel Corporation
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
   * IN THE SOFTWARE.
   *
   * Authors:
   *    Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
   *    Jerome Anand <jerome.anand@intel.com>
   *    based on VED patches
   *
   */
  
  /**
   * DOC: LPE Audio integration for HDMI or DP playback
   *
   * Motivation:
   * Atom platforms (e.g. valleyview and cherryTrail) integrates a DMA-based
   * interface as an alternative to the traditional HDaudio path. While this
   * mode is unrelated to the LPE aka SST audio engine, the documentation refers
   * to this mode as LPE so we keep this notation for the sake of consistency.
   *
   * The interface is handled by a separate standalone driver maintained in the
   * ALSA subsystem for simplicity. To minimize the interaction between the two
   * subsystems, a bridge is setup between the hdmi-lpe-audio and i915:
   * 1. Create a platform device to share MMIO/IRQ resources
   * 2. Make the platform device child of i915 device for runtime PM.
   * 3. Create IRQ chip to forward the LPE audio irqs.
   * the hdmi-lpe-audio driver probes the lpe audio device and creates a new
   * sound card
   *
   * Threats:
   * Due to the restriction in Linux platform device model, user need manually
   * uninstall the hdmi-lpe-audio driver before uninstalling i915 module,
   * otherwise we might run into use-after-free issues after i915 removes the
   * platform device: even though hdmi-lpe-audio driver is released, the modules
   * is still in "installed" status.
   *
   * Implementation:
   * The MMIO/REG platform resources are created according to the registers
   * specification.
   * When forwarding LPE audio irqs, the flow control handler selection depends
   * on the platform, for example on valleyview handle_simple_irq is enough.
   *
   */
  
  #include <linux/acpi.h>
  #include <linux/device.h>
  #include <linux/irq.h>
  #include <linux/pci.h>
  #include <linux/pm_runtime.h>
  
  #include "i915_drv.h"
  #include <linux/delay.h>
  #include <drm/intel_lpe_audio.h>
  
  #define HAS_LPE_AUDIO(dev_priv) ((dev_priv)->lpe_audio.platdev != NULL)
  
  static struct platform_device *
  lpe_audio_platdev_create(struct drm_i915_private *dev_priv)
  {
  	struct drm_device *dev = &dev_priv->drm;
  	struct platform_device_info pinfo = {};
  	struct resource *rsc;
  	struct platform_device *platdev;
  	struct intel_hdmi_lpe_audio_pdata *pdata;
  
  	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
  	if (!pdata)
  		return ERR_PTR(-ENOMEM);
  
  	rsc = kcalloc(2, sizeof(*rsc), GFP_KERNEL);
  	if (!rsc) {
  		kfree(pdata);
  		return ERR_PTR(-ENOMEM);
  	}
  
  	rsc[0].start    = rsc[0].end = dev_priv->lpe_audio.irq;
  	rsc[0].flags    = IORESOURCE_IRQ;
  	rsc[0].name     = "hdmi-lpe-audio-irq";
  
  	rsc[1].start    = pci_resource_start(dev->pdev, 0) +
  		I915_HDMI_LPE_AUDIO_BASE;
  	rsc[1].end      = pci_resource_start(dev->pdev, 0) +
  		I915_HDMI_LPE_AUDIO_BASE + I915_HDMI_LPE_AUDIO_SIZE - 1;
  	rsc[1].flags    = IORESOURCE_MEM;
  	rsc[1].name     = "hdmi-lpe-audio-mmio";
  
  	pinfo.parent = dev->dev;
  	pinfo.name = "hdmi-lpe-audio";
  	pinfo.id = -1;
  	pinfo.res = rsc;
  	pinfo.num_res = 2;
  	pinfo.data = pdata;
  	pinfo.size_data = sizeof(*pdata);
  	pinfo.dma_mask = DMA_BIT_MASK(32);
  
  	pdata->num_pipes = INTEL_INFO(dev_priv)->num_pipes;
  	pdata->num_ports = IS_CHERRYVIEW(dev_priv) ? 3 : 2; /* B,C,D or B,C */
  	pdata->port[0].pipe = -1;
  	pdata->port[1].pipe = -1;
  	pdata->port[2].pipe = -1;
  	spin_lock_init(&pdata->lpe_audio_slock);
  
  	platdev = platform_device_register_full(&pinfo);
  	kfree(rsc);
  	kfree(pdata);
  
  	if (IS_ERR(platdev)) {
  		DRM_ERROR("Failed to allocate LPE audio platform device\n");
  		return platdev;
  	}
  
  	pm_runtime_no_callbacks(&platdev->dev);
  
  	return platdev;
  }
  
  static void lpe_audio_platdev_destroy(struct drm_i915_private *dev_priv)
  {
  	/* XXX Note that platform_device_register_full() allocates a dma_mask
  	 * and never frees it. We can't free it here as we cannot guarantee
  	 * this is the last reference (i.e. that the dma_mask will not be
  	 * used after our unregister). So ee choose to leak the sizeof(u64)
  	 * allocation here - it should be fixed in the platform_device rather
  	 * than us fiddle with its internals.
  	 */
  
  	platform_device_unregister(dev_priv->lpe_audio.platdev);
  }
  
  static void lpe_audio_irq_unmask(struct irq_data *d)
  {
  }
  
  static void lpe_audio_irq_mask(struct irq_data *d)
  {
  }
  
  static struct irq_chip lpe_audio_irqchip = {
  	.name = "hdmi_lpe_audio_irqchip",
  	.irq_mask = lpe_audio_irq_mask,
  	.irq_unmask = lpe_audio_irq_unmask,
  };
  
  static int lpe_audio_irq_init(struct drm_i915_private *dev_priv)
  {
  	int irq = dev_priv->lpe_audio.irq;
  
  	WARN_ON(!intel_irqs_enabled(dev_priv));
  	irq_set_chip_and_handler_name(irq,
  				&lpe_audio_irqchip,
  				handle_simple_irq,
  				"hdmi_lpe_audio_irq_handler");
  
  	return irq_set_chip_data(irq, dev_priv);
  }
  
  static bool lpe_audio_detect(struct drm_i915_private *dev_priv)
  {
  	int lpe_present = false;
  
  	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
  		static const struct pci_device_id atom_hdaudio_ids[] = {
  			/* Baytrail */
  			{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x0f04)},
  			/* Braswell */
  			{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x2284)},
  			{}
  		};
  
  		if (!pci_dev_present(atom_hdaudio_ids)) {
  			DRM_INFO("HDaudio controller not detected, using LPE audio instead\n");
  			lpe_present = true;
  		}
  	}
  	return lpe_present;
  }
  
  static int lpe_audio_setup(struct drm_i915_private *dev_priv)
  {
  	int ret;
  
  	dev_priv->lpe_audio.irq = irq_alloc_desc(0);
  	if (dev_priv->lpe_audio.irq < 0) {
  		DRM_ERROR("Failed to allocate IRQ desc: %d\n",
  			dev_priv->lpe_audio.irq);
  		ret = dev_priv->lpe_audio.irq;
  		goto err;
  	}
  
  	DRM_DEBUG("irq = %d\n", dev_priv->lpe_audio.irq);
  
  	ret = lpe_audio_irq_init(dev_priv);
  
  	if (ret) {
  		DRM_ERROR("Failed to initialize irqchip for lpe audio: %d\n",
  			ret);
  		goto err_free_irq;
  	}
  
  	dev_priv->lpe_audio.platdev = lpe_audio_platdev_create(dev_priv);
  
  	if (IS_ERR(dev_priv->lpe_audio.platdev)) {
  		ret = PTR_ERR(dev_priv->lpe_audio.platdev);
  		DRM_ERROR("Failed to create lpe audio platform device: %d\n",
  			ret);
  		goto err_free_irq;
  	}
  
  	/* enable chicken bit; at least this is required for Dell Wyse 3040
  	 * with DP outputs (but only sometimes by some reason!)
  	 */
  	I915_WRITE(VLV_AUD_CHICKEN_BIT_REG, VLV_CHICKEN_BIT_DBG_ENABLE);
  
  	return 0;
  err_free_irq:
  	irq_free_desc(dev_priv->lpe_audio.irq);
  err:
  	dev_priv->lpe_audio.irq = -1;
  	dev_priv->lpe_audio.platdev = NULL;
  	return ret;
  }
  
  /**
   * intel_lpe_audio_irq_handler() - forwards the LPE audio irq
   * @dev_priv: the i915 drm device private data
   *
   * the LPE Audio irq is forwarded to the irq handler registered by LPE audio
   * driver.
   */
  void intel_lpe_audio_irq_handler(struct drm_i915_private *dev_priv)
  {
  	int ret;
  
  	if (!HAS_LPE_AUDIO(dev_priv))
  		return;
  
  	ret = generic_handle_irq(dev_priv->lpe_audio.irq);
  	if (ret)
  		DRM_ERROR_RATELIMITED("error handling LPE audio irq: %d\n",
  				ret);
  }
  
  /**
   * intel_lpe_audio_init() - detect and setup the bridge between HDMI LPE Audio
   * driver and i915
   * @dev_priv: the i915 drm device private data
   *
   * Return: 0 if successful. non-zero if detection or
   * llocation/initialization fails
   */
  int intel_lpe_audio_init(struct drm_i915_private *dev_priv)
  {
  	int ret = -ENODEV;
  
  	if (lpe_audio_detect(dev_priv)) {
  		ret = lpe_audio_setup(dev_priv);
  		if (ret < 0)
  			DRM_ERROR("failed to setup LPE Audio bridge\n");
  	}
  	return ret;
  }
  
  /**
   * intel_lpe_audio_teardown() - destroy the bridge between HDMI LPE
   * audio driver and i915
   * @dev_priv: the i915 drm device private data
   *
   * release all the resources for LPE audio <-> i915 bridge.
   */
  void intel_lpe_audio_teardown(struct drm_i915_private *dev_priv)
  {
  	struct irq_desc *desc;
  
  	if (!HAS_LPE_AUDIO(dev_priv))
  		return;
  
  	desc = irq_to_desc(dev_priv->lpe_audio.irq);
  
  	lpe_audio_platdev_destroy(dev_priv);
  
  	irq_free_desc(dev_priv->lpe_audio.irq);
  }
  
  
  /**
   * intel_lpe_audio_notify() - notify lpe audio event
   * audio driver and i915
   * @dev_priv: the i915 drm device private data
   * @pipe: pipe
   * @port: port
   * @eld : ELD data
   * @ls_clock: Link symbol clock in kHz
   * @dp_output: Driving a DP output?
   *
   * Notify lpe audio driver of eld change.
   */
  void intel_lpe_audio_notify(struct drm_i915_private *dev_priv,
  			    enum pipe pipe, enum port port,
  			    const void *eld, int ls_clock, bool dp_output)
  {
  	unsigned long irqflags;
  	struct intel_hdmi_lpe_audio_pdata *pdata;
  	struct intel_hdmi_lpe_audio_port_pdata *ppdata;
  	u32 audio_enable;
  
  	if (!HAS_LPE_AUDIO(dev_priv))
  		return;
  
  	pdata = dev_get_platdata(&dev_priv->lpe_audio.platdev->dev);
  	ppdata = &pdata->port[port - PORT_B];
  
  	spin_lock_irqsave(&pdata->lpe_audio_slock, irqflags);
  
  	audio_enable = I915_READ(VLV_AUD_PORT_EN_DBG(port));
  
  	if (eld != NULL) {
  		memcpy(ppdata->eld, eld, HDMI_MAX_ELD_BYTES);
  		ppdata->pipe = pipe;
  		ppdata->ls_clock = ls_clock;
  		ppdata->dp_output = dp_output;
  
  		/* Unmute the amp for both DP and HDMI */
  		I915_WRITE(VLV_AUD_PORT_EN_DBG(port),
  			   audio_enable & ~VLV_AMP_MUTE);
  	} else {
  		memset(ppdata->eld, 0, HDMI_MAX_ELD_BYTES);
  		ppdata->pipe = -1;
  		ppdata->ls_clock = 0;
  		ppdata->dp_output = false;
  
  		/* Mute the amp for both DP and HDMI */
  		I915_WRITE(VLV_AUD_PORT_EN_DBG(port),
  			   audio_enable | VLV_AMP_MUTE);
  	}
  
  	if (pdata->notify_audio_lpe)
  		pdata->notify_audio_lpe(dev_priv->lpe_audio.platdev, port - PORT_B);
  
  	spin_unlock_irqrestore(&pdata->lpe_audio_slock, irqflags);
  }
  